1. Field of the Invention
The invention relates to conductive fabric. More particularly, the invention relates to conductive fabric that includes conductive yarn and non-conductive yarn, in which a portion of the conductive yarn is electrically insulated from the other conductive yarn and an external member.
2. Description of Related Art
Conductive fabric that includes conductive yarn is known, and is used for heaters and various sensors and the like using conductivity. For example, this kind of conductive fabric is used for a seat cover of a vehicle seat, and is used as a seat cover provided with a seat heater or a capacitance seating sensor.
When passing current through the conductive fabric that includes conductive yarn, the conductive yarn is often connected to another conductive connecting member at an end portion of the conductive fabric. The connecting member is further connected to a power supply or a control device or the like. Japanese Patent Application Publication No. 2010-245006 (JP 2010-245006 A) describes one method for connecting the conductive yarn to the connecting member at the end portion of the conductive fabric. This method involves removing a portion of insulating fiber (i.e., non-conductive yarn) that forms cloth material, separating it into a cloth material main body and a cloth material piece, and exposing a plurality of conductive wires (i.e., conductive yarn) from this separated portion. Then the connecting member is wrapped around the conductive wires that are exposed from this separated portion and the conductive wires are sewn in place, such that the conductive wires are electrically connected to the connecting member.
A method such as this is preferable as a method for electrically connecting all of the conductive yarn present in a given region in the conductive fabric to the connecting member. However, when the conductive fabric is used as a heater, for example, there may be cases in which conductive yarn that is to be electrically connected to the connecting member is adjacent to or mixed in the same region with conductive yarn that is to be electrically insulated from the connecting member and not connected to it, such as when adjusting the output of the heater by the number (i.e., the density) of conductive yarns that are carrying current (i.e., energized), or when a heated location and a non-heated location are provided in adjacent regions in a single conductive fabric. In such a case, the method that involves bundling the conductive wires exposed from the separated portion and wrapping the connecting member around them is unable to be used as it is.
For example, as shown in FIG. 5, with the method described in JP 2010-245006 A above, a conductive yarn 42 is first exposed from a separated portion 44, and then if a conductive yarn that is not to be electrically connected to the connecting member, i.e., a non-used conductive yarn 42b, is cut at a location of an end edge 41a of a conductive fabric 41, the conductive yarn that is not to be electrically connected to the connecting member is able to be set using the method described above. If, when a sheet-like connecting member that has conductivity is attached to the end edge 41a of the conductive fabric 41, the conductive member of the cut surface of the non-used conductive yarn 42b will not be connected, electrical insulation between the non-used conductive yarn 42b and the connecting member is ensured. However, in actuality, when the non-used conductive yarn 42b is only cut at the location of the end edge 41a of the conductive fabric 41, conductive material that is exposed at the cross-section of the cut non-used conductive yarn 42b tends to contact the connecting member, and as a result, an electrical connection with the connecting member ends up being formed.
Even if the cut surface does not contact the connecting member in the connecting member connecting step, if force strong enough to bendably deform the conductive fabric 41 or the connecting member is applied to the conductive fabric 41 or the connecting member while current is flowing to a current-carrying conductive yarn 42a (i.e., a conductive yarn that will be energized) that is connected to the connecting member, for example, the connecting member might easily contact the cut surface of the non-used conductive yarn 42b, and the non-used conductive yarn 42b may easily contact the current-carrying conductive yarn 42a that is close to the non-used conductive yarn 42b. If this happens, current will be supplied to the non-used conductive yarn 42b via the connecting member, and a short will occur between the non-used conductive yarn 42b and the current-carrying conductive yarn 42a that is close to this non-used conductive yarn 42b. 
Thus, a method may be employed that involves attaching the connecting member after covering the portion where the current-carrying conductive yarn 42a has been cut at the location of the end edge 41a of the conductive fabric 41, with an insulating member such as insulating tape-like cloth material or the like. With this method, insulation of the end portion of the non-used conductive yarn with respect to the connecting member is able to be ensured, but an insulating member that is a member separate from the conductive fabric 41 is required.